Fuel System: The chicken or the egg?..............fuel line protocol:-)

[Hawklover]

Just want to seek a consensus of opinion here........I will be changing (after 50 years) the 3/8 and 1/4 inch fuel lines in the Avanti.

The line(s) will be realized with Cunifer.

As to double flaring the ends.........would I be better served flaring one end, then rolling out the required length of 3/8 line..in this case flare one end which will screw into the T drain block,then continue up to the rubber hose attached to the fuel tank.........then flair another piece of 3/8 and run up to the fuel pump?

I know the return line does not require any flairs or nuts.

Thanks as always for the opinions:-)

[Mike Van Veghten]

Fuel lines are NOT double flared.
Only brake lines have the folded over flare and the fittings made for that. Fuel line fittings are not made for the double flare. For the double flare to be safe, more threads are required for the extra material that will be inserted into the fitting.
Plus the fuel line pressure is no where near the pressure within the brake system.

Mike

[Hawklover]

Mike the reason I want to double flare is more for the potential vibration protection. And since the line I will use is mostly used for brake line, it will easily accept a double flair on the end. Also the T block I will use has the in and out ports made to accept double flair nuts.

Fuel lines are NOT double flared.
Only brake lines have the folded over flare and the fittings made for that. Fuel line fittings are not made for the double flare. For the double flare to be safe, more threads are required for the extra material that will be inserted into the fitting.
Plus the fuel line pressure is no where near the pressure within the brake system.

Mike

[bezhawk]

Every Studebaker fuel line I have worked on WAS double flared from the factory.

[Hawklover]

Brad I did not know this, but now I feel what I want to do is not "overkill' :-).........I also purchased entire coils of Cunifer, this way I know I will have enough material to do the job.

Every Studebaker fuel line I have worked on WAS double flared from the factory.

[sweetolbob]

I like the choice of cunifer lines. 3/8" is not the easiest steel line size to flare and cunifer should make it less difficult. I'd flare the one end before I cut the line to length, that way if you mess up the first flare you have a second chance.

A tip on flaring, don't leave the end flat as cut, put a slight taper on it. Secondly, if you are having trouble during the flaring process a little lube can help but not before you have the tubing securely clamped in the holder.

And lastly, be sure to put the flare fitting on the line, in the correct orientation, before you flare the second end, don't ask how I know.

Bob

[rusty nut garage]

I respectfully disagree. Fuel lines were and should be double flared.

Fuel lines are NOT double flared.
Only brake lines have the folded over flare and the fittings made for that. Fuel line fittings are not made for the double flare. For the double flare to be safe, more threads are required for the extra material that will be inserted into the fitting.
Plus the fuel line pressure is no where near the pressure within the brake system.

Mike

[Hawklover]

Forgot one thing.........where a steel line goes into a rubber hose

I respectfully disagree. Fuel lines were and should be double flared.

[StudeRich]

Another thing that may not matter to you if bigger is better!
The Jet Thrust Engine and Avanti Fuel Lines were not 3/8". Only the one from the fuel pump or Fuel Filter to Carb. was 3/8" all the other Fuel supply lines were 5/16".

[Mike Van Veghten]

I've removed, now four fuel line runs from four various Studebakers.
In all four...NOT a one at ANY joint, was double flared..!

It's just extra work for no gain.
But go for it, it's your car.

Mike

[PlainBrownR2]

To throw an extra monkey wrench into the works, the '63 Daytona that I'm working on, has no double flares either. In fact, it doesn't have any single flares, or brass fittings of any type in the fuel line. The fuel line is all one 5/16 piece, from the gas tank to the fuel pump, and is connected at both ends with a short segment of rubber fuel hose. The fuel hose is just pushed over the end of the steel line with no flare, like it was a hose barb, and clamped with simple those simple wire clamps that Studebaker used. I mean this fuel system is as simple as simple gets!

The car was originally a 259/Flightomatic, so it was your run of the mill, bread and butter production Daytona.

[Jerry Forrester]

Forgot one thing.........where a steel line goes into a rubber hose

On steel lines where a rubber hose attaches to it, I put the first half of a double flare on the steel line.

[Jerry Forrester]

I like the choice of cunifer lines. 3/8" is not the easiest steel line size to flare and cunifer should make it less difficult. I'd flare the one end before I cut the line to length, that way if you mess up the first flare you have a second chance.

A tip on flaring, don't leave the end flat as cut, put a slight taper on it. Secondly, if you are having trouble during the flaring process a little lube can help but not before you have the tubing securely clamped in the holder.

And lastly, be sure to put the flare fitting on the line, in the correct orientation, before you flare the second end, don't ask how I know.

Bob

I don't think you will find any mechanic that has more than a few years experience that hasn't made THAT mistake. (If he'll tell you the truth).
Just two days ago, Robert was running new brake lines on a 1967 Fairlane GT. He made up the right rear line and went to install it. The original line had a 3/8" line nut on one end and a 7/16" line on the other end (the bk. cyl. end) and he had put a 3/8" on both ends. He cut the flare off, pulled the nut off the line, turned around and did something else and turned back around and slid the same 3/8 nut back onto the line and put a beautiful double flare on. Just as he was taking the line out of the flaring tool he realised what he had done. You should have heard the expletives come out of him. We've all done it.

[Hawklover]

Rich, the line from the Avanti gas tank to the pump is 3/8, the line from the pump to the carb is 5/16.

Another thing that may not matter to you if bigger is better!
The Jet Thrust Engine and Avanti Fuel Lines were not 3/8". Only the one from the fuel pump or Fuel Filter to Carb. was 3/8" all the other Fuel supply lines were 5/16".

[Hawklover]

Brown, I do not doubt you, but on my Avanti the ends of the line had flairs.

To throw an extra monkey wrench into the works, the '63 Daytona that I'm working on, has no double flares either. In fact, it doesn't have any single flares, or brass fittings of any type in the fuel line. The fuel line is all one 5/16 piece, from the gas tank to the fuel pump, and is connected at both ends with a short segment of rubber fuel hose. The fuel hose is just pushed over the end of the steel line with no flare, like it was a hose barb, and clamped with simple those simple wire clamps that Studebaker used. I mean this fuel system is as simple as simple gets!

The car was originally a 259/Flightomatic, so it was your run of the mill, bread and butter production Daytona.